1. Technical Field
The present invention relates in general to data processing systems and in particular to multi-tasking data processing systems. Still more particularly, the present invention relates to methods which permit the direct manipulation of icons from one application to another within a multi-tasking data processing system.
2. Background Art
Early microcomputers or "personal" computers were designed to provide independent computing power to an individual user. Although designed initially for stand-alone operation, it has become common for individual computers to be coupled together or to a main frame computer by means of a computer network. In recent years the personal computer has become so sophisticated that many are now capable of "multi-tasking," that is, the concurrent performance or interleaved execution of two or more tasks.
Multi-tasking is generally accomplished in a personal computer environment by utilization of multiple view ports or "windows," each of which displays information relating to a different application. Examples of such multi-tasking systems include Windows, published by Microsoft, Inc. and OS/2 Presentation Manager, published by International Business Machines Corporation. With either of the aforementioned multi-tasking systems it is possible to provide a "tokenized" or miniature representation of individual applications, generally referred to as "icons." These icons may be displayed within a window and are thus available to a user of that window. This technique is possible when an application draws, maintains, and positions icons for tasks that it may provide within its window. Utilization of these icons by another independent application is not possible without a published set of complex programming interfaces. Likewise, the movement of these icons from the application to another window is not possible without such interfaces.
If the application providing function via icons are structured such that they are independent of the application displaying the icons, an existing data transfer protocol may be utilized to more simply accomplish the transfer of the icon and the associated application function from one window to another. A protocol known as Dynamic Data Exchange (DDE) utilized by both Windows and OS/2 Presentation Manger may be used for this technique.
DDE is a protocol for interprocess communication which consists of a small set of messages and data structures designed to support the interaction between two processes. The communications model utilized by DDE is based upon a client/source application relationship wherein the client application initiates a conversation with the appropriate source application and data then flows from the source application to the client application, supporting the icon disposed therein. For a more detailed description of DDE see Microsoft Systems Journal, November 1987, page 13.
While DDE represents an important step forward in multi-tasking environments, it has at least one short fall which must be addressed. A user may desire to transfer an icon from one application to a second client application. Under existing protocols this is a time consuming process which requires a complex programming interface and which may not be accomplished directly. Therefore, it should be obvious that a need exists for an improved method whereby iconic representations of selected applications may be directly manipulated by a user so that an application may be easily transferred to a second client application.